KR100983833B1 - Crankshaft - Google Patents

Abstract

The invention is formed in particular of a large diesel engine, having at least one axle journal 2 and at least one connecting rod journal 3 that is radially offset to the axle journal. A crankshaft for a short hoisting motor. The axle journal 2 and the connecting rod journal 3 are separated from the crank arm 1 which interconnects, and the axle journal 2 and / or the connecting rod journal 3 are crank arms. A gearing connection piece 5 which engages with the corresponding bore 4 of (1) and engages the crank arm 1 via a contractive connection, the gear connection being rearward in the insertion direction. Is provided with a region 7 having a relatively large diameter and an region 8 in the insertion direction ahead tapered with respect to the region. The region 8 in front of the gear connection 5 in the insertion direction has cones 9 and 10 connected to the region 7 in the rear of the region and tapered in the insertion direction and on the crank arm 1. By having a blocking device which prevents the axial movement of the gear connection 5 with respect to the crankshaft according to the invention, it is possible to achieve a relatively large torque which can be transmitted.

Axle journal, connecting rod journal, short hoist motor, crankshaft, crank arm, bore, gear connection, disconnect

Description

Crankshaft {CRANKSHAFT}

1 is a cross-sectional view partially cut the crankshaft according to the present invention.

FIG. 2 is a partial view of a blocking ring forming a blocking device based on the example according to FIG. 1.

3 is a view in the form of a blocking web formed in the gear connection, as an alternative to the embodiment according to FIGS. 1 and 2.

4 is a view of another embodiment with a cone formed in the region behind the gear connection and forming a blocking device.

FIG. 5 is another alternative view with a front region of the gear connection with two cones opposite each other. FIG.

Figure 6 is a partial view of the prior art with gear connections with steps.

The present invention relates to a crankshaft for a short hoist motor, in particular formed of a large diesel engine, having at least one axle journal and at least one connecting rod journal offset radially to the axle journal. Is away from the interconnecting crank arm, the axle journal and / or the connecting rod journal have a gear connection that engages with the corresponding bore of the crank arm and engages the crank arm via a retraction connection, the gear connection being rearward in the insertion direction. Has an area with a relatively large diameter and an area ahead of the insertion direction tapered with respect to the area.

Homogeneous crankshafts are described in DK-PS 122 682. In the case of large engines, in order to reduce the specific gravity of the assembly, it is essential that the crankshaft passing through all cylinders is composed of small parts. In this case, the crankshaft and the connecting rod journal as well as the axle journal, as well as the crankshaft, in which the substantially same kind of axle journal connected to the corresponding crank arm and the shrink connection are formed in the corresponding crankarm. The crankshafts contracted in the corresponding bores of are distinguished.

For a short hoist motor, one can start from the fact that the radial spacing between the axle journal and the connecting rod journal is within or even less than the entire journal radial region. However, in order to not weaken the crank arm too much due to the bores arranged in the gear connection, refer to the device shown in DK-PS 122 682 above, where the front area is the rear area since the front and rear areas of the gear connection have mutual steps. The diameter becomes smaller. In this case, it is necessary to make a contractive connection, and the margin of the journal for each corresponding bore diameter so far has been a fixed percentage of the bore diameter. Thus, the region behind the gear connection, which has a relatively large diameter and a correspondingly large margin, expands the corresponding region of the crank arm after the contractive connection is made, thus having a relatively small margin and a relatively small diameter in the anterior region as implied in FIG. There is a risk of a gap between the area in front of the gear connection provided and the bore section of the crank arm arranged in this front area. Therefore, if necessary, the entire power flow is forced to move through the rear region of the gear connection. This undesirably acts to increase the transmittable torque.

It is an object of the present invention, starting from this problem, to improve the crankshaft of the kind mentioned at the outset in a simple and inexpensive way, while avoiding the disadvantages of well-known devices, so that it is possible to transmit a relatively high torque.

It is an object of the present invention to provide a blocking device in which the front region of the gear connection in the insertion direction is connected to the rear region of this region and has a taper in the insertion direction, which prevents the axial movement of the gear connection 5 with respect to the crank arm. device).

In this way, the disadvantages of the prior art described at the outset can be completely avoided while maintaining their advantages. The cone connected to the area behind the gear connection eliminates the step between the gear connection and the resulting crank arm bore, which ensures no gaps and ensures reliable shrinkage connections throughout the length of the gear connection. do. Nevertheless, the diameter of the front conical end can be relatively small, so that a relatively large amount of material stops on the crank arm side and prevents the crank arm from weakening. On the other hand, however, the cone diameter in the middle is much larger than the diameter of the front end, so it preferably acts on the transmittable torque. The cone shape of the gear connection results in axially acting power. The resulting axial motion results in a smaller contact width in the area behind the gear connection and stops the contractive connection in the front area. However, this axial movement is stopped due to the blocking device provided.

Preferred and improved forms of the measures are set out in the dependent claims.

In a particularly preferred embodiment the blocking device comprises at least one locking ring, which is engaged with a groove on the circumferential side of the contacting journal and a groove open on the bore side of the crank arm. All. Since the blocking ring is preferably relatively wide, the compression acting in the axial direction is relatively small. Another advantage of this form is that the blocking ring is particularly suitable for use and can be made of a material different from the crankshaft material, thus ensuring particularly high stability.

The blocking ring is preferably formed of an open ring with a slot. As a result, the blocking ring is in the form of a piston ring, and the blocking ring can be easily installed according to the type of the piston ring.

In another preferred embodiment of the present invention, the length of the side grooves corresponds at least to the ring width by adding the degree of shrinkage to be considered. Through this scheme, it can be seen that the blocking ring can be inserted into the groove in the bore side when installed, so that the gear connection can be easily inserted into the crank arm side bore.

In another preferred form of the above measures the blocking device comprises at least one web formed on the gear connection or the crank arm side bore wall and at least partially rotating. The webs mesh with the grooves of the opposing parts, respectively, and their height corresponds at most to the degree of shrinkage to be considered. This embodiment has the advantage that no additional parts are required.

In any case, the blocking device is preferably provided in the boundary region between the front and rear regions of the gear connection. This confirmed that the bending stresses acting on the engines of the blocking device are relatively small. The experiments also showed that, considering this approach, stress concentrations do not occur in the crank arm region.

In another embodiment, the gear connection has a cone that rises in the insertion direction to form the blocking device, the increase in the cone corresponding to the degree of shrinkage that should be considered at best. In this case, an additional radial force is preferably generated by the axial force, which preferably acts on the magnitude of the transferable torque.

Other preferred forms and improvements of the above solutions are set forth in the remaining dependent claims, and can be more fully understood from the following description of the embodiments based on the drawings.

The present invention is mainly applied to a large engine, in particular a ship driving, and is applied to a two-stroke large diesel engine having a large piston diameter and a small hoist. An example of a large apparatus is a 12 cylinder large diesel engine having a cylinder bore diameter of 980 mm. In this engine, the hoist is reduced to about 1200 mm in order to increase the speed at conventional 2400 mm. These examples are of course not limited to this.                     

The base crankshaft of FIG. 1 comprises a crank arm 1, with the axle journal 2 on the one hand from the crank arm and the connecting rod journal 3 radially offset against the axle journal on the other hand. Away. The radial spacing between the axle journal 2 and the connecting rod journal 3 is less than half of the journal diameter total. 1 depicts an axle journal 2 and a connecting rod journal 3. In the case of crankshafts for large engines, it is natural to have a plurality of axle journals arranged coaxially in turn and a plurality of connecting rod journals which are mutually offset and parallel to the shaft in accordance with the desired ignition order.

The illustrated axle journal 2 is engaged with the crank arm 1 via a contractive connection. The connecting rod journal 3 shown is formed in the crank arm 1. Of course, it is also contemplated that the connecting rod journal 3 is coupled to the crank arm 1 via a contractive connection, or the connecting rod journal 3 as well as the axle journal 2 is also coupled to the crank arm 1 via a contractive connection. You can try The latter embodiment may be particularly preferred for large engines with very heavy parts.

All journals, ie axle journals 2, which are engaged with the adjacent crank arm via a retractive connection, engage the corresponding bore 4 of the crank arm 1 and engage the gear connection 5 which is fixed to the crank arm by the retractive connection. Include. The gear connection has a region behind the insertion direction (shown by arrow 6), here a cylindrical region 7 with a relatively large diameter corresponding to the diameter of the axle journal 2 and the region before the insertion direction 8. The front end diameter of this region is relatively small compared to the diameter of the rear region 7. The crank arm 1 thus has sufficient thickness in the region between the front end of the gear connection 5 of the axle journal 2 and the connection region of the connecting rod journal 3. In the embodiment according to FIG. 1 the front end 8 of the gear connection 5 has a circumferential contour which is formed as a truncated cone. The truncated cone is represented by a cone 9 for simplicity. The cone 9 always extends between the region and the front end thereof, which are connected to the region 7 behind the gear connection 5 without step. The bore 4 of the crank arm 1 has a corresponding contour with a cylindrical section disposed in the rear region 7 and a conical section disposed in the front region 8. The cone 9 evenly tapers the area in front of the gear connection 5, from the diameter of the rear region 7 to the diameter of the front end reduced therein.

Because of the inclination of the cone 9, an axial force is created which is caused by the radial force occurring in the shrinking process and which is out of the insertion direction. In order to prevent this axial force from pushing the gear connection 5 back, a blocking device is provided which prevents the axial movement of the gear connection 5. The blocking device comprises a blocking ring 10 which rotates in the embodiment according to FIG. 1, the blocking ring being on the circumferential side groove 11 and the same side of the gear connection 5 and of the crank arm 1. Engage in grooves 12 that open towards the bore surface. The blocking ring 10 is harder than the material on which the crankshaft is based, and is preferably made of spring steel, and is formed relatively wide in the radial direction.

As shown in FIG. 2, the blocking ring 10 has a slot 13 on the circumferential surface side. The blocking ring 10 can thus be expanded in accordance with the shape of the piston ring upon installation. The blocking ring 10 is inserted into the groove 12 open toward the bore surface of the heated crank arm 1 at the time of installation, and the groove on the circumferential surface of the gear connecting portion 5 due to the spring action when the gear connecting portion 5 is pushed in. Mesh with (11). To enable this process, the groove 12 has a depth at least corresponding to the radial width of the blocking ring 10 minus the degree of radial contraction that occurs in the groove 12 region. The degree of shrinkage is subtracted when the crank arm 1 is heated at installation. The blocking ring 10 is arranged in the transition region between the rear cylindrical region 7 and the front conical region 8 of the gear connection 5, thus bending the blocking ring 19 in the region of the crank arm 1. In addition to the requirement, the stress concentration can be particularly small.

In the case of the underlying embodiment of FIG. 3, a fully or partially rotating web 14 formed in the gear connection 5 is provided as a blocking organ, the web being opened toward the bore of the crank arm 1. Meshes with the corresponding groove 15. The maximum h of the web 14 relative to the diameter of the gear connection 5, here the diameter of the region 7 behind the gear connection 5, is at most expected in the area of the crank arm 1 groove 15. Corresponds to the degree of contraction. It was thus confirmed that the gear connection 5 supporting the web 14 can be inserted into the corresponding bore 4 of the crank arm being heated. While cooling of the crank arm 1 is in progress, the web 14 engages with this groove 15 in plane. The groove may have radial redundancy to prevent constraining force. In the example shown, a small margin in the axial direction is presented.

The web 15 is enclosed on both sides to prevent notch stress of the side channels 16. Otherwise, the embodiment according to FIG. 3 corresponds to the embodiment according to FIG. 1. This applies equally to the arrangement of the webs 14 forming the blocking device in the boundary region between the rear region 7 and the front region 8 of the gear connection 5.                     

Another embodiment is shown in FIG. 4. The region 7 behind the insertion direction of the gear connection 5 then has a conical surface area (indicated by the cone 17 below) which rises in the insertion direction. The cone 17 is thus tapered opposite to the cone 9 which is arranged in the region 8 in front of the gear connection 5. The same applies to the crank arm 1 bore 4, which is arranged at the gear connection 5. The bore 4 has a rotary groove 18 in the transition region between the sections arranged behind the gear connection 5 and in the front region 7, 8 to prevent notch stress.

The increase (h ') of the cone 17 relative to the rear diameter of the region behind the gear connection 5, i.e. the difference between the maximum and minimum radius of the region 7 behind the gear connection 5 is at most 1. The gear connection 5 can be inserted into the bore 4 of the crank arm 1 being heated, as this corresponds to the degree of shrinkage expected in the region behind the bore 4. An axial movement of the gear connection 5 with respect to the crank arm 1 cannot occur because of the inclination of the cone 17 opposite to the inclination of the cone 9. Because of the axial forces generated in the cone 9 region, the radial forces acting on the cone 17 region rise, thereby increasing the load of the shrinkage connection.

In the other embodiment, which is the basis of FIG. 5, the region 8 in front of the gear connection 5 is divided into two sections. That is, the first section is formed by a truncated truncated cone (hereinafter referred to as cone 19) and connected to the rear region 7, and a truncated truncated cone (hereinafter referred to as cone 20). And is divided into a second section which is connected to the cone 19. Cone 20, as opposed to cone 19, serves here as a blocking device that prevents axial movement of the gear connection 5 with respect to the crank arm 1. The difference between the minimum radius of the two cones 19, 20 and the radius of the cone 20 arranged in front of the gear connection 5 in the radial direction, ie the increase h ', is at most cones 19, 20. Corresponds to the degree of contraction expected in the transition region between the crank arm 1 bore 4 sections disposed in the. The section 7 behind the gear connection 5 can be cylindrical here.

Some embodiments of the invention have been described above. However, the examples are not final. Other embodiments are also conceivable that are not described in relatively detail. For example, the use of elastic blocking pins to form blocking devices. It is likewise conceivable to have a number of blocking devices that are the same or different in every gear connection 5 area. Thus, the present invention is not limited to the illustrated embodiment.

The blocking device comprises at least one blocking ring, the blocking ring meshing with grooves on the circumferential surface of the contact journal and grooves open on the bore surface of the crank arm. Since the blocking ring is preferably relatively wide, the compression acting in the axial direction is relatively small. The blocking ring is particularly suitable for use and may be made of a material different from the crankshaft material, thus ensuring a particularly high stability.

Claims (12)

A crank arm having an axle journal 2 and at least one connecting rod journal 3 radially offset to the axle journal, wherein the axle journal 2 and the connecting rod journal 3 are interconnected. Away from (1), at least one of the axle journal (2) and the connecting rod journal (3) engages a corresponding bore (4) of the crank arm (1) and through the contractive connection the crank arm (1) And a gear connecting portion 5 engaged with the gear connecting portion, the gear connecting portion having an area 7 having a relatively large diameter behind the insertion direction and an area 8 in the insertion direction forward tapered with respect to the area. As crankshaft for hoist motor, The region 8 in front of the gear connection 5 in the insertion direction is provided with cones 9 and 10 connected to the region 7 in the rear of the region and tapered in the insertion direction, and with respect to the crank arm 1 It is provided with a blocking device for preventing the axial movement of the gear connecting portion 5, The blocking device comprises at least one blocking ring 10, the blocking ring being grooved toward the circumferential surface of the gear connecting portion 5 and groove 12 facing the bore surface of the crank arm 1. Crankshaft characterized in that the mesh. delete The method of claim 1, Crankshaft, characterized in that the blocking ring (10) is formed as an open ring having a radial slot (13). The method of claim 3, The crankshaft, characterized in that the blocking ring 10 is made of a hard material as compared to the material on which the crankshaft is based. The method of claim 4, wherein The crankshaft, characterized in that the blocking ring 10 is made of spring steel (spring steel). The method according to any one of claims 3 to 5, Crankshaft, characterized in that the depth of the groove (12) opened towards the bore surface corresponds to at least the radial width of the blocking ring (10) subtracting the degree of shrinkage expected in the groove (12) region. The method of claim 1, The blocking device comprises at least one web 14 which is formed on the wall of the gear connection 5 or the crank arm side bore 4 and at least partially rotates, the webs each having a corresponding groove of opposite parts ( 15, wherein the radial height h corresponds at most to the degree of shrinkage expected in the groove 15 area. The method according to any one of claims 1, 3 to 5, or 7, The crankshaft, characterized in that the blocking device is provided in the transition region between the rear and front regions (7, 8) of the gear connection (5). The method of claim 1, The gear connection 5 has cones 17 and 20 which rise in the insertion direction to form a blocking device, the rising height h 'of the cone being at most the corresponding area of the crank arm side bore 4. Crankshaft, characterized in that corresponding to the degree of shrinkage. 10. The method of claim 9, Crankshaft, characterized in that the region behind the gear connection (5) (7) has a cone (17) which at least partially rises in the insertion direction. The method of claim 10, The crankshaft, characterized in that the front region (8) of the gear connecting portion (5) has a cone (20) connected to the cone (9) tapered in the insertion direction and rising in the insertion direction. The method according to any one of claims 1, 3 to 5, 7, or 9 to 11, The crankshaft is a crankshaft, characterized in that the crankshaft for large diesel engines.

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